Stabilized distillate fuel oil



United States Patent 3,003,858 STABILIZED DISTILLATE FUEL OIL Harry J. Andress, .lr., Pitman, and Paul Y. C. Gee, Woodbury, N.J., assignors to Socony Mobil Oil Company, Inc., a corporation of New York No Drawing. Filed Jan. 7, 1958, Ser. No. 707,457 7 Claims. (Cl. 44-62) This invention relates to the improvement of non-lubricating petroleum fractions. It is more particularly concerned with distillate fuel oils containing additives adapted to inhibit the appearance of sediment during prolonged storage periods, to prevent screen-clogging, and to prevent rusting of ferrous metal surfaces.

It is well known that fuel oils are prone to form sludge or sediment during periods of prolonged storage. This sediment, of course, has an adverse effect on burner operation, because it has a tendency to clog screens and nozzles. In addition to sediment formed during storage, most fuel oils contain other impurities, such as rust, dirt, and entrained water. The sediment and impurities tend to settle out on equipment parts, such as nozzles, screens, filters, etc., thereby clogging them and causing the equipment to fail.

A further factor, incident to the storage and handling of fuel oils, is the breathing of storage vessels. This results in the accumulation of considerable amounts of water in the tanks, which presents a problem of rusting in the tanks. Then, when the oil is removed for transportation, suflicient water may be carried along to cause rusting of ferrous metal surfaces in pipelines, tankers, and the like.

Generally, it has been the practice to overcome the aforedescribed difiiculties with a separate additive for each purpose, i.e., with a sediment inhibitor, an antiscreen clogging agent, and an antirust agent. The use of several addities, however, gives rise to problems of additive compatibility, thus restricting the choice of additive combinations. In addition, of course, the use of a plurality of additives unduly increases the cost of the fuel. It has been proposed to overcome two difficulties, e.g., sedimentation and screen clogging, with one additive. Insofar as is known, however, no single addition agent has been found effective against sedimentation, screen and nozzle clogging, and rusting of ferrous metal surfaces.

It has now been found that all three problems, i.e., sedimentation, screen clogging, and rusting, can be solved by the use of a single fuel oil addition agent. It has been discovered that a distillable fuel oil containing minor amounts of certain heteropolymer amic acids and amine salts thereof is eifectively inhibited, simultaneously, against all three aforementioned difliculties.

Accordingly, it is a broad object of this invention to provide a fuel oil having properties improved with a minimum number of addition agents. Another object is to provide a fuel oil having a single additive adapted to inhibit sedimentation, to prevent screen clogging, and to prevent rusting of ferrous metal surfaces with which it comes in contact. A specific object is to provide a fuel oil that contains certain heteropolymer amic acids or amine salts thereof that achieve these results. Other objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description.

The present invention provides a distillate fuel oil containing a minor amount, sufficient to inhibit sedimentation and screen clogging and to prevent rusting of ferrous metal surfaces in contact therewith, of a material selected from the group consisting of (1) an amic acid produced by reacting a heteropolymer of maleic acid anhydride and a l-olefin, having 2 to 18 carbon atoms,

with an aliphatic primary amine containing between about 4 and about 30 carbon atoms per molecule, without the evolution of water; and (2) amine salts of (1) with aliphatic primary amine containing between about 4 and about 30 carbon atoms per molecule.

The addition agents utilizable in the fuel oil compositions of this invention are amic acids of certain olefinrnaleic acid anhydride heteropolymers with aliphatic primary amines, and the aliphatic primary amine salts thereof. The heteropolymer is produced by copolymerizing equimolar amounts of a l-olenfin and maleic acid anhydride. The l-olefin reactant should contain between about 2 carbon atoms and about 18 carbon atoms per molecule. The reactants are heated together, either in bulk, or in the presence of a suitable solvent, such as, benzene, toluene, xylene, dioxane, or carbon tetrachloride, at temperatures varying between about C. and about C. Preferably, the copolymerization is carried out in the presence of a peroxide catalyst, such as benzoyl peroxide. The amount of peroxide used is between about one percent and about 5 percent, by weight of the reactants. The time required to complete the copolymerization varies between about one hour and about 4 hours.

The amic acids contemplated herein are produced by warming the olefin-maleic acid anhydride copolymer with an aliphatic primary amine having between about 4 and about 30 carbon atoms per molecule to form amic acid. There is used one mole of amine per mole of maleic acid anhydride in the copolymer. The reaction is carried out by heating the mixture of anhydride and amine at a temperature of 65--90 C. for a period of time varying between one and 3 hours. The addition occurs readily without the formation of water. The salt of the heteropolymer amic acid can be made readily by warming equimolar quantities of the amic acid with an aliphatic primary amine having between about 4 and about 30 carbon atoms per molecule. The salt-forming amine can be the same amine used in making the amic acid, or it can be a different amine. In the case where the saltforming amine is the same used in the amic acid, the salt can be made by heating two moles of amine with one mole of olefin-maleic acid anhydride heteropolymer under temperatures whereby water is not evolved, i.e., below 90 C.

The amines utilizable in forming the amic acids and the salts thereof are the primary aliphatic amines having between about 4 and about 30 carbon atoms per molecule. These are the monoamines having a single open chain hydrocarbon group attached to a nitrogen. The aliphatic radical can be saturated or unsaturated, and branched-chain or normal chain. Likewise mixtures of these amines, as well as pure amines, can be employed. A very useful and readily available class of primary amines are the tertiary-alkyl, primary, monoamines in which a primary amino (--NH group is attached to a tertiary carbon atom; and mixtures thereof. These amines all contain the terminal group,

Non-limiting examples of the amine reactants are t-butyl primary amine, t-hexyl primary amine, n-hexylamine, n-octylamine, n-octenylamine, t-octyl primary amine, 2-ethylhexylamine, t-decyl primary amine, n-decylamine, t-dodecyl primary amine, n-undecylamine, dodescenylamine, dodecadienylamine, tetradecylamine, t-tetradecyl primary amine, t-octadecyl primary amine, hexadecylamine, octadecenylamine, octadecadieny-l amine, t-eicosyl primary amine, t-docosyl primary amine, t-tetracosyl primary amine, and t-triacontyl primary amine. The amine reactants can be prepared in several ways well known to those skilled in the art. Specific methods of preparing the t-alkyl primary amines are disclosed in the Journal of Organic Chemistry, vol. 20, page 295 et seq. (1955). Mixtures of such amines can be made from a polyolefin fraction (e.g., polypropylene and polybutylene cuts) by first hydrating with sulfuric acid and water to the corresponding alcohol, converting the alcohol to alkyl chloride with dry hydrogen chloride, and finally condensing the chloride with ammonia, under pressure, to produce a t-alkyl primary amine mixture.

The fuel oils that are improved in accordance with this invention are hydrocarbon fractions having an initial boiling point of at least about 100 F. and an end boiling point no higher than about 750 F., and boiling substantially continuously throughout their distillation range. Such fuel oils are generally known as distillate fuel oils. It is to be understood, however, that this term is not restricted to straight-run distillate fractions. The distillate fuel oils can be straight-run distillate fuel oils, catalytically or thermally cracked (including hydrocracked) distillate fuel oils, or mixtures of straight-run distillate fuel oils, naphthas and the like, with cracked distillate stocks. Moreover, such fuel oils can be treated in accordance with well known commercial methods, such as, acid or caustic treatment, hydrogenation, solvent refining, clay treatment, etc.

The distillate fuel oils are characterized by their relatively low viscosities, pour points, and the like. The principal property which characterizes the contemplated hydrocarbons, however, is the distillation range. As mentioned hereinbefore, this range will lie between about 100 F. and about 750 F. Obviously, the distillation range of each individual fuel oil will cover a narrower boiling range falling, nevertheless, within the abovespecified limits. Likewise, each fuel oil will boil substantially continuously throughout its distillation range.

Particularly contemplated among the fuel oils are Nos. 1, 2, and 3 fuel oils used in heating and as diesel fuel oils, and the jet combustion fuels. The domestic fuel oils generally conform to the specifications set forth in ASTM Specifications D396-48T. Specifications for diesel fuels are defined in ASTM Specifications D975-48T. Typical jet fuels are defined in Military Specification MIL-F- 5624B.

The amount of amic acid or amine salt of amic acid additive that is added to the distillate fuel oil in accordance with this invention will depend, of course, upon the intended purpose and the particular amic acid or salt selected, as they are not all equivalent in their activity. Some may have to be used in greater concentrations than others to be effective. In most cases, in which it is desired to obtain all three beneficial results, namely, to inhibit sedimentation, to reduce screen clogging, and to prevent rusting of ferrous metal surfaces, additive concentrations varying between 10 pounds per thousand barrels of oil and about 200 pounds per thousand barrels of oil will be employed. It may not always be desired, however, to accomplish all three aforementioned results. In such cases, where it is desired to effect only one or two results, lower concentrations can be used. Thus, if it is desired only to prevent rust under dynamic conditions, as in a pipeline, it has been found that concentrations as low as about 5 p.p.m., i.e., about one pound of additive per thousand barrels of oil, are effective. In general, therefore, the amount of amic acid or of amine salt of amic acid that can be added to the distillate fuel oil, in order to achieve a beneficial result, will vary generally between about one pound per thousand barrels of oil and about 200 pounds per thousand barrels of oil. Preferably, it will vary between about and about 200 pounds per thousand barrels of oil.

If it is desired, the fuel oil compositions can contain other additives for the purpose of achieving other results. Thus, for example, there can be present foam inhibitors and ignition and burning quality improvers. Examples of such additives are silicones, dinitropropane, amyl nitrate, metal sulfonates, and the like.

The following specific examples are for the purpose of ilustrating the fuel oil compositions of this invention, and of exemplifying the specific nature thereof. It is to be strictly understood, however, that this invention is not to be limited by the particular additives and fuel oils, or to the operations and manipulations described therein. Other amic acids or amine salts thereof and fuel oils, as discussed hereinbefore, can be used, as those skilled in the art will readily appreciate.

AMIC ACIDS AND SALTS The amine reactants used in the specific working examples are mixtures of pure amines. Amine A is a mixture of primary amines having a carbon atom of a tertiary butyl group attached to the amino (NH group and containing 12 to 15 carbon atoms per amine molecule and averaging 12 carbon atoms per molecule. This mixture contains, by weight, about percent tertiary dodecyl amine, about 10 percent tertiary pentadecyl amine, and relatively small amounts, i.e., less than about 5 percent of amines having less than 12 or more than 15 carbon atoms.

Amine B is a mixture of tertiary-alkyl primary amines averaging 18 to 24 carbon atoms per molecule and averaging about 20 carbon atoms per molecule. It has a tertiary carbon atom attached to the -NH group. It contains, by weight, about 40 percent t-octadecyl primary amine, about 30 percent t-eicosyl primary amine, about 15 percent t-docosyl primary amine, about 10 percent t-tetracosyl primary amine, and a small amount, less than 5 percent, other amines as high as t-triacontyl primary amine.

Amine C and Amine D are mixtures of normal aliphatic primary amines having the weight percent compositions set forth in Table I.

TABLE I Normal Amine Tetradecyl Hexadecyl Octadecyl Octadecenyl... Octadecadienyl Example 1 A mixture of 70 grams (0.5 mole) of l-decene, 49 grams (0.5 mole) of maleic acid anhydride and 1.8 grams (1.5%) of benzoyl peroxide was gradually heated with stirring. Heat was turned off at C. The reaction was exothermic and the temperature rose rapidly to 175 C., then dropped. The mixture was stirred at 150 C. for 3 hours to complete copolymerization. The copolymer was diluted with grams of xylene. To the copolymer was added 100 grams (0.5 mole) of Amine A to form an amic acid. The reaction mixture was stirred at 85 C. for 3 hours.

Example 2 A mixture of 70 grams (0.5 mole) of l-decene, 49 grams (0.5 mole) of maleic acid anhydride and 1.8 grams (1.5 of benzoyl peroxide was gradually heated with stirring. Heating Was discontinued at 100 C. The reaction was exothermic and the temperature rose rapidly to 165 C., then dropped. The mixture was stirred at C. for 3 hours to complete copolymerization. The copolymer was diluted with 120 grams of xylene. To the copolymer was added 150 grams (0.5 mole) of Amine D to form an amic acid. The reaction mixture was stirred at 85 C. for 3 hours.

Example 3 A mixture of 56 grams (Vs mole) of l-dodecene, 32.7 grams 6 mole) of maleic acid anhydride, 1.33 grams (1.5%) of benzoyl peroxide and 22 grams of xylene was gradually heated with stirring. Heat was turned off at 95 C. The reaction was exothermic and the temperature rose rapidly to 170 C., then dropped. The mixture was stirred at 150 C. for 2 hours to complete copolymerization. The copolymer was diluted with 103 grams of xylene. To the copolymer was added 67 grams (Vs mole) of Amine A to form an amic acid. The mixture was stirred at 80 C. for one hour and thirty minutes.

Example 4 A mixture of 65.3 grams /a mole) of l-tetradecene, 32.7 grams /2. mole) of maleic acid anhydride, 1.3 grams 1.5%) of benzoyl peroxide and 25 grams of xylene was gradually heated with stirring. Heat was turned off at 100 C. The reaction Was exothermic and the temperature rose rapidly to 127 C., then dropped. The mixture was stirred at 150 C. for 2 hours to complete copolymerization. The copolymer was diluted with 50 grams of xylene. To the copolymer was added 67 grams /3 mole) of Amine A to form an amic acid. The mixture was stirred at 80-85 C. for 2 hours.

Example 5 A mixture of 49 grams (0.25 mole) of l-tetradecene, 24.5 grams (0.25 mole) of maleic acid anhydride, 1.5 grams (2%) of benzoyl peroxide and 25 grams of xylene was gradually heated with stirring. Heat was turned off at 95 C. The reaction was exothermic and the temperature rose rapidly to 117 C., then dropped. The mixture was stirred at 150 C. for 2 hours to complete copolymerization. The copolymer was diluted with 75 grams of xylene. To the copolymer was added 75 grams (0.25 mole) of Amine D to form "an amic acid. The mixture was stirred at 7585 C. for 2 hours.

Example 6 A mixture of 112 grams (0.5 mole) of l-hexadecene, 49 grams (0.5 mole) of maleic acid anhydride (0.5 mole) and 1.6 grams (1%) of benzoyl peroxide was gradually heated with stirring. Heat was turned oil at 100 C. The reaction was exothermic and the temperat ure rose rapidly to 143 C., then dropped. The mixture was stirred at 150 C. for 2 hours to complete copolymerization. The copolymer was diluted with 161 grams of xylene. To the copolymer was added 100 grams (0.5 mole) of Amine A to form an amic acid. The mixture was stirred at 75-80 C. for 3 hours.

Example 7 A mixture of 75 grams'G/s mole) of l-hexadecene, 32.7 grams mole) of maleic acid anhydride and 1.1 grams (1%) of benzoyl peroxide was g radually heated with stirring. Heat was turned off at 100 C. The reaction was exothermic and the temperature rose rapidly to 175 C., then dropped. The mixture was stirred at 150 C. for 3 hours to complete copolymerization. The coplymer was diluted with 108 grams of xylen. To the copolymer was added 100 grams /3 mole) of Amine D to form an amic acid. The mixture was stirred at 8085 C. for 3 hours.

Example 8 A mixture of 84 grams mole) of l-octadecene, 32.7 grams /a mole) of maleic acid anhydride, 2.3 grams (2%) of benzoyl peroxide and 30 grams of xylene was gradually heated with stirring. Heat was turned oil at 95 C. The reaction was exothermic and the temperature rose rapidly to 153 C., then dropped. The mixture was stirred at 150 C. for 2 hours to complete copolymerization. The copolymer was diluted with 120 grams of xylene. To the copolymer was added 67 grams (Vs mole) of Amine A to form an amic acid. The mixture was stirred at -85 C. for 2 hours.

Example 9 A mixture of 42 grams (0.25 mole) of l-dodecene, 24.5 grams (0.25 mole) of maleic acid anhydride, 1.33 grams (2%) of benzoyl peroxide and 10 grams of xylene was gradually heated with stirring. Heat was turned ofi at 100 C. The reaction was exothermic and the temperature rose rapidly to 165 C., then dropped. The mixture was stirred at 145-150 C. for 3 hours to complete copolymerization. The copolymer was diluted with 182 grams of xylene. To the copolymer was added at room temperature 50 grams (0.25 mole) of Amine A to form an amic acid. The mixture was stirred at 65 C. for 1 hour and 30 minutes. To the amic acid was added at room temperature 75 grams (0.25 mole) of Amine D to form an amine salt. The mixture was stirred at 75 C. for 2 hours.

Example 10 A mixture of 42 grams (0.25 mole) of l-dodecene, 24.5 grams (0.25 mole) of maleic acid anhydride, 1.33 grams (2%) of benzoyl peroxide and 10 grams of xylene was gradually heated with stirring. Heat was turned oil at 100 C. The reaction was exothermic and the temperature rose rapidly to 160 C., then dropped. The mixture was stirred at 145150 C. for 4 hours to complete copolymerization. The copolymer was diluted with grams of xylene. To the copolymer was added at room temperature 50 grams (0.25 mole) of Amine A to form an amic acid. The mixture was stirred at 75 C. for 2 hours. To the amic acid was added at room temperature 50 grams (0.25 mole) of Amine A to form an amine salt. The mixture was stirred at 75 C. for 2 hours.

Example 11 A mixture of 42 grams (0.25 mole) of l-dodecene, 24.5 grams (0.25 mole) of maleic acid anhydride, 1.33 grams (2%) of benzoyl peroxide and 10 grams of xylene was gradually heated with stirring. Heat was turned off at C. The reaction mixture was exothermic and the temperature rose rapidly to 165 C., then dropped. The mixture was stirred at l50 C. for 4 hours to complete copolymerization. The copolymer was diluted with 90 grams of xylene. To the copolymer was added at room temperature 50 grams (0.25 mole) of Amine A to form an amic acid. The mixture was stirred at 75 C. for 2 hours. To the amic acid was added at room temperature 32.25 grams (0.25 mole) of Amine C to form an amine salt. 2 hours.

Example 12 A mixture of'63 grams (0.25 mole) of l-octadecene, 24.5 grams (0.25 mole) of maleic acid anhydride, 1.3 grams (1.5%) of benzoyl peroxide and 12 grams of xylene was gradually heated with stirring. Heat was turned oil at 100 C. The reaction was exothermic and the temperature rose rapidly to 164 C., then dropped. The mixture was stirred at C. for 3 hours to complete copolymerization. The copolymer was diluted with 88 grams of xylene. To the copolymer was added at room temperature 50 grams (0.25 mole) of Amine A to form an amic acid. The mixture was stirred at 75 C. for 1 hour and 30 minutes. To the amic acid was added at room temperautre 75 grams (0.25 mole) of Amine D to form an amine salt. The mixture was stirred at 75 C. for 1 hour and 30 minutes.

Example 13 A mixture of 63 grams (0.25 mole) of l-octa-decene,

24.5 grams (0.25 mole) of maleic acid anhydride, 1.3 grams (1.5%) of benzoyl peroxide and 12 grams of xylene was gradually heated with stirring. Heat was The mixture was stirred at 75 C. for

turned off at 100 C. The reaction was exothermic and the temperature rose rapidly to 165 C., then dropped. The mixture was stirred at 150 C. for 3 hours to complete copolymerization. The copolymer was diluted with 88 grams of xylene. To the copolymer was added at room temperature 50 grams (0.25 mole) of Amine A to form an amic acid. The mixture was stirred at 70 C. for 1 hour and 30 minutes. To the amic acid was added at room temperature 50 grams (0.25 mole) of Amine A to form an amine salt. The mixture was stirred at 70 C. for 1 hour.

Example 14 A mixture of 63 grams (0.25 mole) of l-octadecene, 24.5 grams (0.25 mole) of maleic acid anhydride, 1.3 grams (1.5%) of benzoyl peroxide and 100 grams of xylene was gradually heated to 150 C. with stirring. The temperature was kept at 150 C. for 4 hours to complete copolymerization. To the copolymer was added at room temperature 5 0 grams (0.25 mole) of Amine A to form an amic acid. The mixture was stirred at 75 C. for 1 hour and 30 minutes. To the amic acid was added at room temperature 32.24 grams (0.25 mole) of Amine C to form an amine salt. The mixture was stirred at 75 C. for 3 hours.

Example A mixture of 42 grams (0.25 mole) of l-dodecene, 24.5 grams (0.25 mole) of maleic acid anhydride, 1 gram (1%) of benzoyl peroxide and 12 grams of xylene was gradually heated with stirring. Heat was turned off at 100 C. The reaction was exothermic and the temperature rose rapidly to 155 C., then dropped. The mixture was stirred at 150 C. for 3 hours to complete copolymerization. The copolymer was diluted with 88 grams of xylene. To the copolymer was added at room temperature 84 grams (0.25 mole) of Amine B to form an amic acid. The mixture was stirred at 75 C. for 1 hour and minutes.

Example 16 A mixture of 42 grams (0.25 mole) of l-dodecene, 24.5 grams (0.25 mole) of maleic acid anhydride, 1.0 gram (1%) of benzoyl peroxide, and 12 grams of xylene was gradually heated with stirring. Heat was turned off at 100 C. The reaction was exothermic and the temperature rose rapidly to 156 C. and then dropped. The mixture was stirred at 150 C. for 3 hours to complete the copolymerization. The copolymer was diluted with 88 grams of xylene. To the copolymer was added at room temperature 168 grams (0.5 mole) of Amine B to form the amine salt of the amic acid. The mixture was stirred at 75-85 C. for 3 hours.

SEDIMENTATION The test used to determine the sedimentation characteristics of the fuel oils is the 110 F. Storage Test. In this test, a SOO-milliliter sample of the fuel oil under test is placed in a convected oven maintained at 110 F. for a period of 12 weeks. Then, the sample is removed from the oven and cooled. The cooled sample is filtered through a tared asbestos filter (Gooch crucible) to remove insoluble matter. The weight of such matter in milligrams is reported as the amount of sediment. A sample of the blank, uninhibited oil is run along with a fuel oil blend under test. The effectiveness of a fuel oil containing an inhibitor is determined by comparing the weight of sediment formed in the inhibited oil with that formed in the uninhibited oil.

Example 17 The additives described in Examples 1 through 16 were blended in a test fuel oil and the blends were subjected to the 110 F. Storage Test. The test results comparing the blended fuels and uninhibited fuels are set forth in Table II. The test fuel oil is a blend of 60 percent distillate stock obtained from continuous catalytic cracking and 40 percent straight-run distillate stock. It has a boiling range of between about 320 F. and about 640 F. and is a typical No. 2 fuel oil.

TABLE II 110 F. STORAGE TEST-12 Wnnxs Gonc'n, Sediment, Additive of Example lb%l/)1],000 trig/liter SCREEN CLOGGING The anti-screen clogging characteristics of a fuel oil were determined as follows: The test is conducted using a Sundstrand V3 or S1 home fuel oil burner pump with a self-contained 100-mesh Monel metal screen. About 0.05 percent, by weight, of naturally-formed fuel oil sediment, composed of fuel oil, water, dirt, rust, and organic sludge is mixed with 10 liters of the fuel oil. This mixture is circulated by the pump through the screen for 6 hours. Then, the sludge deposit on the screen is washed off with normal pcntane and filtered through a tared Gooch crucible. After drying, the material in Gooch crucible is washed with a 50-50 (volume) acetone-methanol mixture. The total organic sediment is obtained by evaporating the pentane and the acetone-methanol filtrates. Drying and weighing the Gooch crucible yields the amount of inorganic sediment. The sum of the organic and inorganic deposits on the screen can be reported in milligrams recovered or converted into percent screen clogging.

Example 18 Using the test fuel oil described in Example 17, blends of the additives of Examples 1 through 16 in this fuel were prepared. Each blend was subjected to the Screen Clogging test, as aforedescribed. Test results are set forth in Table III.

TABLE III SCREEN CLOGGING Concn, Screen Additive of Examplelbs/1,000 Clogging,

bhls. percent RUSTING The method used for testing anti-rust properties of the fuel oils was the ASTM Rust Test D-665 operated for 48 Example 19 Blends of the additives described in Examples 1 through 16 in the fuel oil described in Example 17 were subjected to the ASTM Rust Test D-665. Pertinent data are set forth in Table IV.

TABLE IV ASTM RUST TEST Additive of Example- Concn,

p.p.m.

Test Result Fail. Pass. Pass. Pass. Pass. Pass. Pass. Pass. Pass. Pass. Pass. Pass. Pass. Pass. Pass. Pass. Pass.

H an cncncncncntocncnwwtoonq It will be apparent, from the data set forth in Tables II through IV, that the l-olefin-maleic anhydride amic acids of this invention and amine salts thereof are highly effective to reduce sedimentation and screen clogging and to inhibit rusting of ferrous metal surfaces. As is to be expected, results will vary among specific materials used. In order to accomplish any given improvement, many of the additives can be used in relatively small amounts, as for dynamic rust prevention. if, on the other hand, it is desired to accomplish all the aforementioned beneficial results, this can be accomplished at the practical additive concentration of 50-100 pounds per thousand barrels of fuel oil.

Although the present invention has been described with preferred embodiments, it is to be understood that modifications and variations may be resorted to, without departing from the spirit and scope of this invention, as those skilled in the art will readily understand. Such variations and modifications are considered to be within the purview and scope of the appended claims.

What is claimed is:

1. A distillate fuel oil containing a minor amount, sufficient to inhibit sedimentation and screen clogging and to prevent rusting of ferrous metal surfaces in contact therewith, of a material selected from the group consisting of (1) an amic acid of a heteropolymer of maleic acid anhydride and a l-olefin, having between about 2 and about 18 carbon atoms, with an unsubstituted aliphatic primary amine containing between about 4 and about 30 carbon atoms per molecule, and (2) amine salts of (l) with unsubstituted aliphatic primary amine containing between about 4 and about 30 carbon atoms per molecule; said heteropolymer being produced by reacting equimolar amounts of maleic acid anhydride and said l-olefin at temperatures of between about 100 C. and about 175 C., for a period of time varying between about one hour and about 4 hours.

2. A distillate fuel oil containing between about one and about 200 pounds per thousand barrels of oil of a material selected from the group consisting of (1) an amic acid of a heteropolymer of maleic acid anhydride and a l-olefin, having between about 2 and about 18 carbon atoms, with an unsubstituted aliphatic primary amine containing between about 4 and about 30 carbon atoms per molecule, and (2) amine salts of (1) with unsubstituted aliphatic primary amine containing between about 4 and about 30 carbon atoms per molecule; said heteropolymer being produced by reacting equimolar amounts of maleic acid anhydride and said l-olefin at temperatures of between about C. and about C., for a period of time varying between about one hour and about 4 hours.

3. A distillate fuel oil containing between about 10 pounds and about 200 pounds per thousand barrels of oil of an amic acid of a heteropolymer of maleic acid anhydride and dodecene-l with a mixture of unsubstituted aliphatic primary amines containing between about 18 and about 24 carbon atoms per molecule and having a tertiary carbon atom attached to the nitrogen atom; said heteropolymer being produced by reacting equimolar amounts of maleic acid anhydride and dodecene-l at temperatures of between about 100 C. and about 175 C., for a period of time varying between about one hour and about 4 hours.

4. A distillate fuel oil containing bewteen about 10 and about 200 pounds per thousand barrels of oil of an amic acid of a heteropolymer of maleic acid anhydride and tetradecene-l with a mixture of unsubstituted aliphatic primary amines containing between about 12 and about 15 carbon atoms per molecule and having a tertiary carbon atom attached to the nitrogen atom; said heteropolymer being produced by reacting equimolar amounts of maleic acid anhydride and tetradecene-l at temperatures of between about 100 C. and about 175 C., for a period of time varying between about one hour and about 4 hours.

5. A distillate fuel oil containing between about 10 pounds and about 200 pounds per thousand barrels of oil of an amine salt of an amic acid of a heteropolymer of maleic acid anhydride and tetradecene-l with a mixture of unsubstituted aliphatic primary amines containing between about 16 and about 18 carbon atoms per molecule, with a mixture of unsubstituted aliphatic primary amines containing between about 16 and about 18 carbon atoms per molecule as the salt-forming amine; said heteropolymer being produced by reacting equimolar amounts of maletic acid anhydride and tetradecene-l at temperatures of between about 100 C. and about 175 C., for a period of time varying between about one hour and about 4 hours.

6. A distillate fuel oil containing between about 10 pounds and about 200 pounds per thousand barrels of oil of an amic acid of a heteropolymer of maleic acid anhydride and hexadecene-l with a mixture of unsubstituted aliphatic primary amines containing between about 12 and about 15 carbon atoms per molecule and having a tertiary carbon atom attached to the nitrogen atom; said heteropolymer being produced by reacting equimolar amounts of maleic acid anhydride and hexadecene-l at temperatures of between about 100 C. and about 175 C., for a period of time varying between about one hour and about 4 hours.

7. A distillate fuel oil containing between about 10 pounds and about 200 pounds per thousand barrels of oil of an amic acid of a heteropolymer of maleic acid anhydride and hexadecene-l with a mixture of unsubstituted aliphatic primary amines containing between about 16 and about 18 carbon atoms per molecule; said heteropolymer being produced by reacting equimolar amounts of maleic acid anhydride and hexadecene-l at temperatures of between about 100 C. and about 175 C., for a period at time varying between about one hour and about 4 ours.

References Cited in the file of this patent UNITED STATES PATENTS 2,313,565 McDowell et a1 Mar. 9, 1943 2,451,370 Alderson Oct. 12, 1948 2,615,845 Lippincott et a1. Oct. 28, 1952 2,698,316 Giammaria Dec. 28, 1952 2,699,427 Smith et al Jan. 11, 1955 UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No. 3,003,858 October 10, 1961 Harry J. Andress 'Jr. et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below;

Column 7 Y line 23 for "32. 24 grams" read 32. 25 grams Signed and sealed this 3rd day of April 1962.

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer DAVID L. LADD Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No. 3,003,858 October 10, 1961 Harry J, Andress, 'Jr., et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below Column 7, line 23, for "32.24 grams" read 32.25 grams Signed and sealed this 3rd day of April 1962.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Commissioner of Patents Attesting Officer UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No. 3,003,858 October 10, 1961 Harry J, Andress, -Jr., et a1.

It is hereby certified that error eppeaz 's in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 7 line 23, for "32. 24 grams" read 32.25 grams Signed and sealed this 3rd day of April 1962' SEAL) Attest:

DAVID L. LADD Commissioner of Patents ERNEST W. SWIDER Attesting Officer 

1. A DISTILLATE FUEL OIL CONTAINING A MINOR AMOUNT, SUFFICIENT TO INHIBIT SEDIMENTATION AND SCREEN CLOGGING AND TO PREVENT RUSTING OF FERROUS METAL SURFACES IN CONTACT THEREWITH, OF A MATERIAL SELECTED FROM THE GROUP CONSISTING OF (1) AN AMIC ACID OF A HETEROPOLYMER OF MALEIC ACID ANHYDRIDE AND A 1-OLEFIN, HAVING BETWEEN ABOUT 2 AND ABOUT 18 CARBON ATOMS, WITH AN UNSUBSTITUTED ALIPHATIC PRIMARY AMINE CONTAINING BETWEEN ABOUT 4 AND ABOUT 30 CARBON ATOMS PER MOLECULE, AND (2) AMINE SALTS OF (1) WITH UNSUBSTITUTED ALIPHATIC PRIMARY AMINE CONTAINING BETWEEN ABOUT 4 AND ABOUT 30 CARBON ATOMS PER MOLECULE, SAID HETEROPOLYMER BEING PRODUCED BY REACTING EQUIMOLAR AMOUNTS OF MALEIC ACID ANHYDRIDE AND SAID 1-OLEFIN AT TEMPERATURES OF BETWEEN ABOUT 100*C. AND ABOUT 175* C., FOR A PERIOD OF TIME VARYING BETWEEN ABOUT ONE HOUR AND ABOUT 4 HOURS. 